CVE-2017-6745 in Videoscape Distribution Suite
Summary
by MITRE
A vulnerability in the cache server within Cisco Videoscape Distribution Suite (VDS) for Television 3.2(5)ES1 could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted appliance. The vulnerability is due to excessive mapped connections exhausting the allotted resources within the system. An attacker could exploit this vulnerability by sending large amounts of inbound traffic to a device with the intention of overloading certain resources. A successful exploit could cause the device to reload, resulting in a DoS condition. Cisco Bug IDs: CSCvc39260.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/07/2021
The vulnerability identified as CVE-2017-6745 resides within the cache server component of Cisco Videoscape Distribution Suite (VDS) for Television version 3.2(5)ES1, representing a critical denial of service weakness that can be exploited remotely without authentication. This flaw specifically affects the system's resource management capabilities within the cache server architecture, where the vulnerability manifests through excessive mapped connections that ultimately deplete the allocated system resources. The Cisco Videoscape Distribution Suite operates as a comprehensive television distribution platform that manages content delivery and caching for broadcast and cable television systems, making this vulnerability particularly concerning for media distribution environments. The issue stems from inadequate resource tracking and connection management mechanisms within the cache server's memory mapping subsystem, which fails to properly handle high volumes of concurrent connection requests.
The technical exploitation of this vulnerability occurs when an unauthenticated remote attacker systematically sends massive volumes of inbound traffic to the targeted appliance, specifically targeting the cache server's connection handling mechanisms. This attack vector leverages the fundamental flaw in resource allocation where mapped connections accumulate beyond the system's capacity limits, causing resource exhaustion that triggers automatic system reloads. The vulnerability's impact is amplified by the fact that the attack requires no authentication credentials, making it accessible to any external party capable of reaching the device over the network. The connection exhaustion occurs at the kernel level within the cache server's memory management subsystem, where the system's ability to map and maintain network connections becomes overwhelmed by the volume of malicious traffic. This type of resource exhaustion attack aligns with common denial of service patterns and can be classified under CWE-400 as an uncontrolled resource consumption vulnerability, specifically manifesting as a resource leak or exhaustion condition.
The operational consequences of a successful exploit result in complete service disruption for the affected appliance, forcing automatic system reloads that can last several minutes and potentially cause temporary loss of video content delivery services. This DoS condition directly impacts broadcast operations and content distribution systems that rely on the Cisco Videoscape Distribution Suite for their television delivery infrastructure, potentially affecting thousands of subscribers during the service interruption period. The vulnerability's exploitation timeline typically involves sustained traffic flooding over extended periods, with the system eventually reaching its connection limits and triggering the automatic reload mechanism. Organizations utilizing this software in production environments face significant operational risks, as the attack can occur without any prior warning or detection, and the system recovery process requires manual intervention or automated failover mechanisms to restore service availability.
Mitigation strategies for CVE-2017-6745 should focus on implementing network-level protections including rate limiting and connection tracking mechanisms to prevent the accumulation of excessive mapped connections. Organizations should deploy firewall rules and access control lists to restrict inbound traffic to the cache server ports, particularly limiting the number of concurrent connections from individual source addresses. Cisco has released patches and software updates addressing this vulnerability, which should be prioritized for deployment across all affected systems within the organization's television distribution infrastructure. Network administrators should implement monitoring solutions to detect unusual connection patterns and resource consumption spikes that may indicate exploitation attempts. The implementation of connection pooling and proper resource allocation limits within the cache server configuration can help prevent the accumulation of excessive mapped connections. Additionally, organizations should consider implementing redundant systems and automated failover mechanisms to minimize service disruption during exploitation attempts, aligning with ATT&CK framework technique T1499 for resource exhaustion attacks and emphasizing defensive measures against network-based DoS conditions.